Translates to ‘Spiny Skin’ sea stars and urchins slow moving and marine adult = radial, larval = bilateral Thin epidermis covered in hard plates often with bumps or spines
Translates to ‘Spiny Skin’ sea stars and urchins slow moving and marine adult = radial, larval = bilateral Thin epidermis covered in hard plates often with bumps or spines Possess a unique water vascular system flexible hydraulic canals = tube feet
All chordates share 4 traits Some only in embryo stages Notochord Dorsal, hollow nerve cord Pharyngeal slits Muscular, Post-anal tail 2 invertebrates groups that are more related to vertebrates Cephlachordata (lancelets) Urochordates (tunicates)
Possess skeletal and nervous systems simple to complex backbones lots of unique genes (eg. HOX) Derived trait = neural crest special cells near neural tube in embryo give rise to many vertebrate traits e.g.. teeth, skull cartilage, etc
Evolved while predators where developing Cambrian period Ocean origins (first 150 mya) Vertebrate: series of bones that make up the vertebral column 57,000 species Vertebrates with limbs colonized land 365 mya Amphibians Reptiles (w/ birds) Mammals
Only members of vertebrates without jaws sister group of jawless fish Have rudimentary backbones more cartilage than bone Hagfish escape by releasing slime researched to stop bleeding in surgery
Only members of vertebrates without jaws sister group of jawless fish Have rudimentary backbones more cartilage than bone Hagfish escape by releasing slime researched to stop bleeding in surgery Many Lamprey are parasitic on fish invaded Great Lakes native to Chesapeake Bay
‘Cartilage fishes’: skeletons mostly cartilage often with calcium originated 400 mya Streamlined body for swift swimming poor maneuverability near constant motion Birth via eggs or young develop inside mother Modern species diversity shrinking
Phylogeny: large new vertebrate group with bony endoskeletion fishes = aquatic groups Add lungs/lung derivatives to phylogeny
Important derived traits for fishes: operculum: swim bladder: Ray-finned: bony rays that support fins trout, sea horses, eels Lobe-finned: rod-shaped bone surrounded by muscle in fins lungfish, Coelacanths, earliest tetrapods
A fish has a density of about 1.076 freshwater has a density of 1.0 saltwater has a density of 1.026 Bone is nearly twice as dense as cartilage Swimming is energy expensive resting on the bottom may not be practical Evolution of the swim bladder set fish free
Lobe fins gradually evolved into limbs Tetrapods colonized land 365 mya move away from fish-like vertebrates Tetrapod derived trait = limbs with digits supports weight digits efficiently support movement
Fossil found in river bed Selection of many terrestrial traits head separated from body by a neck add vertebrate to allow head to swing bones of pelvis fuse to backbone many species lost gills (became ears)
Include salamanders, frogs and caecilians 6,000 species caecilians lost legs Rely on skin for gas exchange live in moist habitats Name means ‘dual life’ some have aquatic tadpole larvae more related to metamorphosis gills → legs, lungs, eardrums
Lizards, snakes, turtles, crocs and BIRDS many extinct groups small (16mm) to large (12m) Scales with keratin Lay shelled eggs on land Most reptiles are ectothermic
Lizards, snakes, turtles, crocs and BIRDS many extinct groups small (16mm) to large (12m) Scales with keratin Lay shelled eggs on land Most reptiles are ectothermic
Large adaptive radiation post dinosaurs predators, herbivores, flying, aquatic Monotremes = platypus (egg laying) Maruspials = pouched mammals Eutherians = placental mammals Derived Trait: Mammary glands produce milk for offspring Derived Trait: Hair insulation/water saver Derived Trait: Kidney waste removing/water saving organ